FEAT: improved ar codec to be able decode also System V (or GNU) variant files

Author: Oldes

src/mezz/codec-ar.reb

@@ -2,7 +2,7 @@ REBOL [
 	title: "REBOL 3 codec for AR files"
 	name: 'codec-ar
 	author: rights: "Oldes"
-	version: 0.0.1
+	version: 0.0.2
 	specification: https://en.wikipedia.org/wiki/Ar_(Unix)
 	history: [7-Oct-2021 "Oldes" {Initial version of the AR decoder}]
 	todo: {AR encoder}
@@ -13,41 +13,72 @@ register-codec [
 	name:  'ar
 	type:  'compression
 	title: "Unix archive file"
-	suffixes: [%.ar %.a]
+	suffixes: [%.ar %.a %.lib]
 
 	decode: function [
-		{Extract content of the AR file}
+		{Extract content of the AR/LIB file}
 		data  [binary! file! url!]
 		return: [block!] "Result is in format: [NAME [DATE UID GID MODE DATA] ...]"
 	] [
 		unless binary? data [data: read data]
-		sys/log/info 'AR ["^[[1;32mDecode AR data^[[m (^[[1m" length? data "^[[mbytes )"]
+		sys/log/info 'AR ["^[[1;32mDecode AR/LIB data^[[m (^[[1m" length? data "^[[mbytes )"]
 		unless parse data ["!<arch>^/" data: to end][return none]
 		bin: binary data
 		out: make block! 32
 
+		long-names: none
+		numbers: system/catalog/bitsets/numeric
+
 		while [58 <= length? bin/buffer][
-			binary/read bin [
-				file: STRING-BYTES 16
-				info: STRING-BYTES 42
-				end:  UI16LE          ;#{600A}
+			info: binary/read bin [
+				STRING-BYTES 16 ; File identifier
+				STRING-BYTES 12 ; File modification timestamp
+				STRING-BYTES 6  ; Owner ID
+				STRING-BYTES 6  ; Group ID
+				STRING-BYTES 8  ; File mode (type and permission)
+				STRING-BYTES 10 ; File size in bytes
 			]
-			unless all [
-				try [info: load info]
-				end = 2656
-				info/1: to date! info/1
-			][ return none]
-
-			data: binary/read bin take/last info
-			if parse file ["#1/" copy len to end ][
-				; BSD variant
+			if 2656 <> binary/read bin 'UI16LE [ ;= #{600A}
+				sys/log/error 'AR "Invalid file header!"
+				return none
+			]
+			file: trim/tail take info
+			real: none
+			forall info [
+				; it may be an empty string in Windows' lib file!
+				try/except [info/1: to integer! info/1][info/1: 0]
+			]
+			; convert timestamp to Rebol value (it may be -1 in *.lib files)
+			info/1: either info/1 <= 0 [none][to date! info/1]
+			size: take/last info
+			data: binary/read bin size
+			if odd? size [
+				if 10 <> binary/read bin 'UI8 [
+					sys/log/error 'AR "Invalid padding!"
+				]
+			]
+			if parse file [opt ["#1" (bsd?: true)] #"/" copy len some numbers to end ][
 				len: to integer! to string! len
-				file: take/part data len       ; real file name in front of the data section
-				file: binary/read file 'string ; removes null padding
+				case [
+					bsd? [
+						;- BSD variant
+						real: take/part data len            ; real file name in front of the data section
+						real: binary/read real-name 'string ; removes null padding
+					]
+					long-names [
+						;- System V (or GNU) variant
+						binary/read long-names [ATZ :len real: STRING]
+					]
+				]
+				if real [append info as file! real]
 			]
 			sys/log/info 'AR ["File:^[[33m" pad copy file 20 mold info]
 			append info data
 			append/only append out as file! file info
+
+			if file = "//" [
+				long-names: data
+			]
 		]
 		new-line/all out true
 		out